docs: def _displayattrs(attrib, expandattrs):
      """
      Helper function to display the attributes of a Node object in lexicographic
      order.
  
      :param attrib: dictionary with the attributes
      :param expandattrs: if True also displays the value of the attributes
      """
      if not attrib:
          return ''
      if expandattrs:
          alist = ['%s=%r' % item for item in sorted(attrib.items())]
      else:
          alist = list(attrib)
      return '{%s}' % ', '.join(alist)